A hybrid vehicle driveline may include an engine that is selectively mechanically coupled to an electric machine via a driveline disconnect clutch. The engine and/or electric machine provide torque to a driveline that includes a transmission. The transmission may include a plurality of fixed gears that may be selected based on vehicle speed and driver demand torque. Transmission clutches allow different gears to be operable at different times. The driveline disconnect clutch and the transmission clutches may both be supplied an operating fluid to apply the clutches. However, a pump supplying operating fluid to both clutches may not have sufficient capacity to supply the driveline disconnect clutch and a transmission clutch without one of the clutches slipping more than a desired amount.
The inventors herein have recognized the above-mentioned disadvantages and have developed a driveline operating method, comprising: delaying a clutch filling boosting phase of a driveline disconnect clutch positioned between an engine and an electric machine until a transmission clutch filling boosting phase reaches a predetermined condition during a power on downshift or a power on upshift.
By delaying application of one clutch while the other clutch is being applied, it may be possible to provide the technical result of smoother driveline operation. In particular, it may be possible to reduce clutch slippage and transmission shifting time by not allowing clutch filling boosting phases for two different clutches to take place at the same time. For example, application of one clutch may be delayed until the other clutch ends its clutch filling boosting phase. As a result, it may be possible to operate both a driveline disconnect clutch and a transmission clutch with a single pump that would otherwise lack capacity to operate both the driveline disconnect clutch and a transmission clutch in a desired manner.
The present description may provide several advantages. In particular, the approach may allow for a lower capacity pump to supply transmission fluid to both a driveline disconnect clutch and a transmission clutch. Further, the approach may reduce the possibility of undesirable driveline operation. Further still, the approach may improve driver satisfaction regarding the vehicle driving experience.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.